TY - JOUR
AB - Frequency-dependent selection on warning color can maintain narrow hybrid zones between unpalatable prey taxa. To measure such selection, we transferred marked Heliconius erato (Lepidoptera: Nymphalidae) in both directions across a 10-km-wide hybrid zone between Peruvian races differing in color pattern. These experimental H. erato were released at four sites, along with control H. erato of the phenotype native to each site. Survival of experimental butterflies was significantly lower than that of controls at two sites and overall. Most selection, measured as differences in survival, occurred soon after release. Selection against foreign morphs was 52% (confidence limits: 25-71%) and was probably due to bird attacks on unusual warning-color morphs (more than 10% of the recaptures had beak marks). Since only three major loci determine the color-pattern differences, this suggests an average selection coefficient of 0.17 per locus, sufficient to maintain the narrow clines in H. erato.
AU - Mallet, James L
AU - Nicholas Barton
ID - 3653
JF - Evolution
TI - Strong natural selection in a warning color hybrid zone
VL - 43
ER -
TY - JOUR
AB - Many species are divided into a mosaic of genetically distinct populations, separated by narrow zones of hybridization. Studies of hybrid zones allow us to quantify the genetic differences responsible for speciation, to measure the diffusion of genes between diverging taxa, and to understand the spread of alternative adaptations.
AU - Nicholas Barton
AU - Hewitt, Godfrey M
ID - 3654
JF - Nature
TI - Adaptation, speciation and hybrid zones
VL - 341
ER -
TY - JOUR
AB - Non-pyramidal neurons in cat Ammon's horn were shown to send their axons to the supramammillary regions (SMR), i.e. the supramammillary nucleus and its vicinities including the supramammillary nucleus and the lateral, posterior and dorsal hypothalamic areas: wheat germ agglutinin-horseradish peroxidase (WGA-HRP) injection into Ammon's horn resulted in labeling of presumed axon terminals in the SMR; and after injecting HRP into the SMR, retrogradely labeled non-pyramidal neurons were seen in Ammon's horn.
AU - Ino, Tadashi
AU - Itoh, Kazuo
AU - Kamiya, Hiroto
AU - Ryuichi Shigemoto
AU - Akiguchi, Ichiro
AU - Mizuno, Noboru
ID - 2522
IS - 1
JF - Brain Research
TI - Direct projections of non-pyramidal neurons of Ammon's horn to the supramammillary region in the cat
VL - 460
ER -
TY - JOUR
AB - Injection of large amounts of a mixture of horseradish peroxidase and wheat germ agglutinin-horseradish peroxidase conjugate into the upper cervical segments of the spinal cord in the Japanese monkey (Macaca fuscata) led to the retrograde labeling of a small number of neuronal cell bodies within the rostral part of the subthalamic nucleus of Luys. Direct projection from the subthalamic nucleus to the spinal cord appeared to be much less prominent in the Japanese monkey than in the cat and rat.
AU - Mizuno, Noboru
AU - Ueyama, Teizo
AU - Itoh, Kazuo
AU - Satoda, Takahiro
AU - Tashiro, Takashi
AU - Ryuichi Shigemoto
ID - 2523
IS - 1
JF - Neuroscience Letters
TI - Direct projections from the subthalamic nucleus of Luys to the spinal cord in the Japanese monkey
VL - 89
ER -
TY - JOUR
AB - Alpha-ketoglutamate (α-KG) reductive amination activity in rat brain was found to be mostly absorbed with an antibody against liver glutamate dehydrogenase. With this and anti-glutamine synthetase antibodies, α-KG reductive amination activity was immunocytochemically shown to coexist with glutamine synthetase activity in astrocytes. The results suggest that astrocytes de novo synthesize glutamate from α-KG and ammonia, and metabolize it to glutamine.
AU - Kaneko, Takeshi
AU - Ryuichi Shigemoto
AU - Mizuno, Noboru
ID - 2524
IS - 1
JF - Brain Research
TI - Metabolism of glutamate and ammonia in astrocyte an immunocytochemical study
VL - 457
ER -
TY - JOUR
AU - Leonid Sazanov
AU - Karavaev, V A
AU - Kukushkin, A K
ID - 1941
JF - J. Phys. Chem-Russia
TI - Mathematical model of photosynthesis regulation accounts for the effects of changes in external conditions and observed oscillations
VL - 52
ER -
TY - JOUR
AB - In this paper we study the problem of polygonal separation in the plane, i.e., finding a convex polygon with minimum number k of sides separating two given finite point sets (k-separator), if it exists. We show that for k = Θ(n), is a lower bound to the running time of any algorithm for this problem, and exhibit two algorithms of distinctly different flavors. The first relies on an O(n log n)-time preprocessing task, which constructs the convex hull of the internal set and a nested star-shaped polygon determined by the external set; the k-separator is contained in the annulus between the boundaries of these two polygons and is constructed in additional linear time. The second algorithm adapts the prune-and-search approach, and constructs, in each iteration, one side of the separator; its running time is O(kn), but the separator may have one more side than the minimum.
AU - Herbert Edelsbrunner
AU - Preparata, Franco P
ID - 4090
IS - 3
JF - Information and Computation
TI - Minimum polygonal separation
VL - 77
ER -
TY - JOUR
AB - An X-ray probe through a polygon measures the length of intersection between a line and the polygon. This paper considers the properties of various classes of X-ray probes, and shows how they interact to give finite strategies for completely describing convex n-gons. It is shown that (3n/2)+6 probes are sufficient to verify a specified n-gon, while for determining convex polygons (3n-1)/2 X-ray probes are necesssary and 5n+O(1) sufficient, with 3n+O(1) sufficient given that a lower bound on the size of the smallest edge of P is known.
AU - Herbert Edelsbrunner
AU - Skiena,Steven S
ID - 4091
IS - 5
JF - SIAM Journal on Computing
TI - Probing convex polygons with X-Rays
VL - 17
ER -
TY - CONF
AU - Herbert Edelsbrunner
ID - 4096
TI - Geometric structures in computational geometry
VL - 317
ER -
TY - CONF
AB - Arrangements of curves in the plane are of fundamental significance in many problems of computational and combinatorial geometry (e.g. motion planning, algebraic cell decomposition, etc.). In this paper we study various topological and combinatorial properties of such arrangements under some mild assumptions on the shape of the curves, and develop basic tools for the construction, manipulation, and analysis of these arrangements. Our main results include a generalization of the zone theorem of [EOS], [CGL] to arrangements of curves (in which we show that the combinatorial complexity of the zone of a curve is nearly linear in the number of curves), and an application of (some weaker variant of) that theorem to obtain a nearly quadratic incremental algorithm for the construction of such arrangements.
AU - Herbert Edelsbrunner
AU - Guibas, Leonidas
AU - Pach, János
AU - Pollack, Richard
AU - Seidel, Raimund
AU - Sharir, Micha
ID - 4097
TI - Arrangements of curves in the plane - topology, combinatorics, and algorithms
VL - 317
ER -
TY - GEN
AU - Coyne, Jerry A
AU - Nicholas Barton
ID - 4315
T2 - Nature
TI - What do we know about speciation ?
VL - 331
ER -
TY - GEN
AU - Nicholas Barton
AU - Jones, Steve
ID - 4316
T2 - Nature
TI - Molecular evolutionary genetics
VL - 332
ER -
TY - CHAP
AU - Nicholas Barton
ED - Myers, Alan A
ED - Giller, Paul S
ID - 4317
T2 - Analytical biogeography
TI - Speciation
ER -
TY - GEN
AU - Nicholas Barton
AU - Jones, Steve
AU - Mallet, James L
ID - 4318
T2 - Nature
TI - No barriers to speciation
VL - 336
ER -
TY - JOUR
AU - Dallas, John F
AU - Nicholas Barton
AU - Dover, Gabriel A.
ID - 3655
IS - 6
JF - Molecular Biology and Evolution
TI - Interracial rDNA variation in the grasshopper Podisma pedestris
VL - 5
ER -
TY - JOUR
AU - Nishimura, Masaki
AU - Ryuichi Shigemoto
AU - Matsubayashi, K
AU - Mimori, Y
AU - Kameyama, Masakuni
ID - 2521
IS - 11
JF - Clinical Neurology
TI - Meningoencephalitis during the pre-icteric phase of hepatitis A - a case report
VL - 27
ER -
TY - BOOK
AB - Computational geometry as an area of research in its own right emerged in the early seventies of this century. Right from the beginning, it was obvious that strong connections of various kinds exist to questions studied in the considerably older field of combinatorial geometry. For example, the combinatorial structure of a geometric problem usually decides which algorithmic method solves the problem most efficiently. Furthermore, the analysis of an algorithm often requires a great deal of combinatorial knowledge. As it turns out, however, the connection between the two research areas commonly referred to as computa tional geometry and combinatorial geometry is not as lop-sided as it appears. Indeed, the interest in computational issues in geometry gives a new and con structive direction to the combinatorial study of geometry. It is the intention of this book to demonstrate that computational and com binatorial investigations in geometry are doomed to profit from each other. To reach this goal, I designed this book to consist of three parts, acorn binatorial part, a computational part, and one that presents applications of the results of the first two parts. The choice of the topics covered in this book was guided by my attempt to describe the most fundamental algorithms in computational geometry that have an interesting combinatorial structure. In this early stage geometric transforms played an important role as they reveal connections between seemingly unrelated problems and thus help to structure the field.
AU - Edelsbrunner, Herbert
ID - 3900
SN - 9783540137221
TI - Algorithms in Combinatorial Geometry
VL - 10
ER -
TY - JOUR
AB - The visibility graph of a finite set of line segments in the plane connects two endpoints u and v if and only if the straight line connection between u and v does not cross any line segment of the set. This article proves that 5n - 4 is a lower bound on the number of edges in the visibility graph of n nonintersecting line segments in the plane. This bound is tight.
AU - Herbert Edelsbrunner
AU - Shen, Xiaojun
ID - 4094
IS - 2
JF - Information Processing Letters
TI - A tight lower bound on the size of visibility graphs
VL - 26
ER -
TY - JOUR
AB - he kth-order Voronoi diagram of a finite set of sites in the Euclidean plane E2 subdivides E2 into maximal regions such that all points within a given region have the same k nearest sites. Two versions of an algorithm are developed for constructing the kth-order Voronoi diagram of a set of n sites in O(n2 log n + k(n - k) log2 n) time, O(k(n - k)) storage, and in O(n2 + k(n - k) log2 n) time, O(n2) storage, respectively.
AU - Chazelle, Bernard
AU - Herbert Edelsbrunner
ID - 4095
IS - 11
JF - IEEE Transactions on Computers
TI - An improved algorithm for constructing kth-order Voronoi diagrams
VL - 36
ER -
TY - JOUR
AB - This paper investigates the existence of linear space data structures for range searching. We examine thehomothetic range search problem, where a setS ofn points in the plane is to be preprocessed so that for any triangleT with sides parallel to three fixed directions the points ofS that lie inT can be computed efficiently. We also look atdomination searching in three dimensions. In this problem,S is a set ofn points inE 3 and the question is to retrieve all points ofS that are dominated by some query point. We describe linear space data structures for both problems. The query time is optimal in the first case and nearly optimal in the second.
AU - Chazelle, Bernard
AU - Herbert Edelsbrunner
ID - 4100
IS - 1
JF - Discrete & Computational Geometry
TI - Linear space data structures for two types of range search
VL - 2
ER -